The same way the living do. You don't actually think that death is the end of existance do you?
The Mormon 'religion' was invented in the 19th century. What did poor souls do for salvation before that?
The "Mormon" religion has existed since before the world began and had many names throughout the centuries. So called "Mormonism" is just the name of the Gospel of Jesus Christ in the Dispensation of the Fulness of Times. Much like it was called "Christianity" during the Dispensation of Grace at the Merdian of Time.
Thus, poor souls have done the same thing for salvation that they have done since the days of Adam. They have called upon The Father in the Name of the Son for forgiveness from sins exercised faith in Him. Trusting that through the merits of His Son, they would be find redemption from the Fall.
I would invite you and everyone else to read the
Book of Mormon for yourselves and come to understand the Atonement of Jesus Christ and our need for His grace in being redeemed from the fall. I invite you to learn about Christ's ministry after His resurrection and to read the testimony of those who witnessed the resurrection. And I would invite you to take the Book of Mormon challenge. Of all the book of scripture, I know only one that invites men to humble themselves before God and ask whether the scripture is true. The Book of Mormon provides an experiment for all men to find out for themselves that it's true:
Behold, I would exhort you that when ye shall read these things, if it be wisdom in God that ye should read them, that ye would remember how merciful the Lord hath been unto the children of men, from the creation of Adam even down until the time that ye shall receive these things, and ponder it in your hearts.
And when ye shall receive these things, I would exhort you that ye would ask God, the Eternal Father, in the name of Christ, if these things are not true; and if ye shall ask with a sincere heart, with real intent, having faith in Christ, he will manifest the truth of it unto you, by the power of the Holy Ghost.
And by the power of the Holy Ghost ye may know the truth of all things. (
Moroni 10:3-5)
That's one of the beauties of the Gospel. I dont have to convince you that it's true. You are under no obligation to take my word for it. Dont believe it because I say so. Find out for yourself. There is a way. I know that from experience. Learn from personal experience from the Holy Spirit. This is a promise given to all men and women.
If the Book of Mormon is true, and I testify that it is, it is one of the most powerful witnesses of Jesus Christ on the face of the earth. It verifies the testimony of the Apostles found in the Bible with a second witness. It either is a record of those who lived in Ancient America brought forth by the Power and Grace of God to stand as an additional witness with the Bible in this Last dispensation. Or it's a fraud. There is no middle ground with it.
The Holy Spirit has testified to me that the Book of Mormon is true. But as I said, you don't have to take my word for it. Find out for yourself. If it is true, that it stands as a testimony that God is active in the world today and is the most important message we can contemplate in this life. You have absolutely nothing to lose by taking the challenge. At worst, you will know and understand Mormons better.
The choice is yours.